fix: pin encoding=utf-8 on text-mode open() reads in TupleFilesystemStoreBackend, InlineStoreBackend, FileDataContext

[CAOShurong]

Fixes #12120: great_expectations wrote store files as UTF-8 unconditionally but read them back with bare open() (locale-ambient). On hosts where the process locale encoding is not UTF-8 (e.g. Windows cp936), this raised UnicodeDecodeError on the very bytes great_expectations itself wrote.

Changes

• tuple_store_backend.py:318 _get() open(filepath) → open(filepath, encoding="utf-8")
• inline_store_backend.py:222 _save_changes() write → open(..., encoding="utf-8")
• file_data_context.py:168 _save_project_config() write → open(..., encoding="utf-8")
• file_data_context.py:194 _load_file_backed_project_config() read → open(..., encoding="utf-8")

Verification

• Reproduced the bug on a Windows host (codepage cp936): bare open() raised UnicodeDecodeError: 'gbk' codec can't decode byte 0x94 / 0xad on the non-ASCII UTF-8 bytes the write path emitted.
• With encoding="utf-8" pinned on the four text-mode open() calls, round-trips succeed under forced PYTHONUTF8=0 / LC_ALL=C.

Regression tests

Added two tests that run under PYTHONUTF8=0 / LC_ALL=C to force the non-UTF-8 codepage:

• test_tuple_store_backend_utf8_pinned_read_roundtrip in tests/data_context/store/test_store_backends.py
• test_file_data_context_utf8_pinned_yml_load in tests/data_context/test_loading_and_saving_of_data_context_configs.py

Both fail against unpatched develop and pass with the fix.

AI-assisted: yes (Hermes General agent, autonomous loop round v6)

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